Viral clearance is essential for manufacturing safe, biotechnology-derived pharmaceuticals such as monoclonal antibodies (mAbs), recombinant proteins, fusion proteins, sera and media, and the like. Regulatory agencies worldwide mandate removal of viral contaminants from a host of products headed into commercial markets. The nanometer-scale of viruses complicates their separation from biopharmaceutical intermediates because the viral particles (due to their size) bind only to the surface of chromatography beads. Virus particles are too large to enter the pores of conventional chromatographic beads. Thus, the binding capacity of conventional chromatographic beads for viruses is much smaller than it is for impurities that can enter and bind within the pores.
Chromatographic beads themselves are a relatively expensive commercial product. To operate at peak levels, the beads must have a very nearly monodisperse particle size, in combination with a tightly-controlled pore size. As a consequence, chromatographic beads are designed for regeneration so that they can be re-used over many purification cycles (to keep manufacturing costs down). While this approach does, in fact, keep material costs in check, it is not without drawback. Most notably, when the beads are to be recycled, the virus-ligand binding must be reversible. In short, once the beads are loaded to their full capacity of virions, the beads must be cleaned of the virus particles. Resin cleaning and lifetime validation costs (while cheaper than purchasing new chromatographic resin for each separation) are considerable.
There remains a long-felt, and unmet need, for a virus-trapping medium that has both high-efficiency and high-capacity for trapping virus particles, and is also sufficiently low in cost that it can be implemented as a one-time, disposable medium for removing viral contamination from biological products.